Now their paths cross again. Grant has learnt of the existence of the Armageddon Storm, a terrifying new Federation superweapon. Only the Liberator can stop it being deployed on the battle-ravaged world of Shorin.

Avon finds herself in a race against time, with the crew’s lives hanging in the balance. But what will Grant do when he finds out about the blood on Avon’s hands.

Liberator Chronicles 3: The Armageddon Storm blew in on Valentine’s Day, setting hearts a-flutter with the return of Del Grant. He steps back on board the Liberator, sounding as if a mere handful of episodes had passed since he took his leave at the end of Countdown, rather than 34 real-life years.

Set in Season C, after the events in Rumours of Death, Del Grant has been hired by rebels on Shorin, whose planet is under threat from a new Federation super-weapon, the mysterious PDX10 – otherwise known as the Armageddon Storm. Grant urgently needs to find Henrik Paxter, the Federation scientist who developed the weapon, and he contacts the Liberator crew to ask for their help. Having sent Vila and Cally down to Shorin to make contact with the rebels, Avon takes the Liberator to the planet Claustrum Prime, where he and Grant go in search of Paxter.

The first episode follows Avon and Grant on their quest to locate the Federation scientist and find out the nature of PDX10. In the second episode, we’re with Cally and Vila on Shorin, as they join the rebels. The third episode focuses again on Avon and Grant, and the terrible implications of the Federation’s weapon.

Although the format of The Armageddon Storm is a return to that of the enhanced audiobook, with a main narrator and additional dialogue scenes, this feels almost like a full-cast drama. There are four narrators, Zen and Orac have spoken lines, and there are two other speaking parts – the rebels Emel and Krale, played respectively by Jan Chappell and Michael Keating. With an epic story spanning three episodes, multiple narrators and loads of dialogue and action scenes, this audiobook is more than enhanced – it’s on steroids.

It was slightly disconcerting at first to have Tarrant and Dayna’s action and dialogue described rather than heard – the all-cast Warship has raised the bar rather high in that respect. However, Avon’s narration of Episodes 1 and 3 felt absolutely right and his scenes with Grant are a great mixture of action and angst. Tom Chadbon sounds exactly the same as he did in Countdown, and their dialogue feels like a natural continuation of their conversations in that episode; picking up the threads from where they had previously left off. The awkwardness, grief and guilt over Anna provide some marvellous moments, set against their desperate race to prevent the weapon’s deployment.

Meanwhile, down on Shorin, Vila and Cally take turns narrating Episode 2, and there’s a lovely, warm dynamic between those characters. It’s nice to hear each character’s impression of the other, and their dialogue scenes are excellent. Once again, Big Finish have given us action-girl Cally, the rebel fighter who controls and uses her telepathic abilities to her advantage, rather than passively being taken over by them. And despite his constant worrying and complaining, Vila has moments of heroism, too.

Episode 3 has Avon again as narrator, picking up the cliff-hangers from both previous episodes and moving the story forward as he and Grant wrestle with their inner demons and external threats, with no small risk to life, limb and Liberator.

It’s a first-rate story, quite dark and brutal in places. Once again there are no clear-cut good guys and bad guys; the guest characters, whether rebels or Federation, have as much moral ambiguity, hidden agendas and ulterior motives as the crew of the Liberator.

As with Big Finish’s other releases, the production values are high. While all the actors’ performances are wonderful, special mention should be made of Michael Keating’s portrayal of the rebel Krale – a character who sounds so unlike Vila that I thought he was played by another actor.

Alistair Lock once again has provided great sound design. All the familiar sounds of Liberator are there, together with multi-layered soundscapes for the other planets, top notch music and sound effects for all the action and battle scenes.

Producer David Richardson said, “The brief I gave for The Armageddon Storm was to deliver a huge action movie that was spread over three episodes.” And that’s how it’s turned out – an epic, three-part adventure with all the quality we’ve come to expect from Big Finish’s Blakes 7 range.

One of Kerr Avon’s oldest friends returns as the crew tries to uncover the deadly secret of the Federation’s latest weapon…

This may not be a full-cast audio like Warship but what it lacks in direct dialogue for Dayna and Tarrant it more than makes up for with its epic length – pretty much the equivalent of four episodes of the original show are devoted to this story.

The first disc follows Avon and Del Grant (Tom Chadbon sounding pretty much like he’s hardly been away) up to a suitable cliffhanger; we then go back to what Vila and Cally have been doing, finishing at their side of the same point. Part three mixes and matches as appropriate. Paul Darrow, Jan Chappell and Michael Keating can’t complain that they’re being given anodyne scripts: this story puts them all through the wringer.

I’m sure there must have been discussions about the breakdown of the first two parts – would it perhaps have worked better if the story were told chronologically, so the danger that the two teams faced were counterpointed more dramatically? There’s a structural similarity to some of The Lord of the Rings here, where Tolkien followed a strand for a long period before doubling back and explaining what else had been going on; it works in a book, but when dramatized, it has its drawbacks. I think it works well as presented, but it would be interesting to hear an alternate mix.

As for the third part: the resolution of the cliffhanger is absolutely right for Blake’s 7 and the third-series characters that this story is using. It’s a slap in the face when it happens, but once the shock has died away, you realise that any other course of action would simply be wrong. And as for the ending – well, you hear Avon use an adjective that you wouldn’t normally associate with him… but which is totally appropriate here.

Cavan Scott, Mark Wright, Ken Bentley and David Richardson, take a bow!